Solar collector including freeze protection system and method of fabrication of heat trap for collector

Abstract From the Canadian patent

A solar energy collector of low cost and high thermal effeciency is disclosed having a heat trap produced by zigzagging a thin strip of polyethylene terephthalate between opposite sides of the trap while wrapping the strip about rows of dowels positioned at opposite sides of the frame of the solar collector. A window of soda lime glass filters UV radiation to inhibit discoloration of the plastic heat trap walls. An absorber plate having fluid pipes therein is positioned underneath the heat trap and a first layer of fiberglass and a second, layer of polyurethene foam are positioned below the absorber plate. The fiberglass layer prevents overheating of the polyurethane foam layer to in turn …